Tubemonkey is so awesome at digging up the audio deals that I love it when I can actually scoop him.
Audible has one of their 2-for-1 sales going on now. As of right now, there are 5 days, 3 hours, and 51 minutes left in the sale.
Choose from hundreds of titles in various categories.
The sale is for members only. However, I assume that members include the "silver" members (the ones who get a choice of only one free book per month), because I am a silver member and I got the announcement.
Go
here to read all about the sale, including checking out the selection of titles.